eV-scale sterile neutrinos from an extra dimension

TL;DR

This paper proposes a model where eV-scale sterile neutrinos arise naturally from a warped extra dimension framework, explaining observed anomalies through a seesaw mechanism with hierarchical neutrino masses.

Contribution

It introduces a novel implementation of the seesaw mechanism in warped extra dimensions to generate eV-scale sterile neutrinos with natural mass hierarchies.

Findings

Hierarchies explained by fluctuations in 5D fermion masses

Seesaw mechanism adapted for extra-dimensional setup

Consistent with short-baseline neutrino anomalies

Abstract

Motivated by the short-baseline neutrino oscillation anomalies that suggest the existence of sterile neutrinos at the eV scale, we construct a scenario of a seesaw mechanism for 3+1 light neutrinos implemented by warped compactification of an extra dimension. As the seesaw mechanism necessitates at least two right-handed neutrinos at mass scales much larger than eV, incorporating an eV-scale sterile neutrino into a seesaw entails large mass hierarchies among the singlet neutrinos. We show that such hierarchies can be naturally explained by moderate fluctuations of the five-dimensional fermion mass parameters.